CVE-2026-35176: openFPGALoader Buffer Overflow Vulnerability

CVE-2026-35176 Overview

CVE-2026-35176 is a heap-buffer-overflow read vulnerability affecting openFPGALoader, an open-source utility for programming FPGAs. The vulnerability exists in the POFParser::parseSection() function in versions 1.1.1 and earlier, allowing out-of-bounds heap memory access when parsing a specially crafted .pof file. Notably, no FPGA hardware is required to trigger this vulnerability, expanding the potential attack surface to any system where openFPGALoader processes user-supplied files.

Critical Impact

Attackers can exploit this heap-buffer-overflow read to access sensitive heap memory contents or cause application crashes, potentially leading to information disclosure or denial of service conditions.

Affected Products

• openFPGALoader version 1.1.1 and earlier
• Systems processing untrusted .pof files with openFPGALoader

Discovery Timeline

• 2026-04-06 - CVE-2026-35176 published to NVD
• 2026-04-07 - Last updated in NVD database

Technical Details for CVE-2026-35176

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read), a memory safety issue that occurs when software reads data past the end or before the beginning of the intended buffer. In the context of openFPGALoader, the POFParser::parseSection() function fails to properly validate input bounds when processing sections within .pof files, which are programming object files used for FPGA configuration.

When a maliciously crafted .pof file is parsed, the function attempts to read beyond allocated heap memory boundaries. This can result in reading adjacent memory contents, potentially exposing sensitive information stored in heap memory, or triggering a crash when accessing unmapped memory regions.

Root Cause

The root cause of this vulnerability lies in insufficient boundary validation within the POFParser::parseSection() function. When parsing section data from a .pof file, the parser does not adequately verify that the declared section length corresponds to the actual available data in the buffer. An attacker can craft a .pof file with malformed section headers that specify lengths exceeding the actual data present, causing the parser to read past buffer boundaries.

Attack Vector

This vulnerability requires local access and user interaction, as an attacker must convince a user to process a malicious .pof file with openFPGALoader. Attack scenarios include:

• Distributing malicious .pof files through file-sharing platforms or repositories
• Sending crafted files via email or messaging as part of a social engineering attack
• Compromising development environments or build pipelines that process .pof files

The vulnerability can be triggered through command-line usage of openFPGALoader when specifying a malicious .pof file as input. Since no FPGA hardware is required, the attack can be executed on any development machine or build server where openFPGALoader is installed.

For detailed technical information regarding the exploitation mechanism, refer to the GitHub Security Advisory.

Detection Methods for CVE-2026-35176

Indicators of Compromise

• Unexpected crashes or segmentation faults when openFPGALoader processes .pof files
• Application errors indicating memory access violations during file parsing
• Abnormal memory usage patterns when processing .pof files of unusual structure

Detection Strategies

• Monitor for abnormal termination of openFPGALoader processes with memory-related error signals (SIGSEGV, SIGBUS)
• Implement file integrity monitoring for .pof files in development environments
• Use memory sanitizers (AddressSanitizer, Valgrind) during development to detect out-of-bounds access
• Deploy endpoint detection solutions to identify exploitation attempts targeting memory corruption vulnerabilities

Monitoring Recommendations

• Enable application crash logging and analysis for openFPGALoader processes
• Monitor file access patterns for .pof files from untrusted sources
• Implement anomaly detection for unusual openFPGALoader execution patterns

How to Mitigate CVE-2026-35176

Immediate Actions Required

• Avoid processing .pof files from untrusted or unverified sources
• Audit systems to identify all instances of openFPGALoader version 1.1.1 and earlier
• Implement strict access controls on development environments using openFPGALoader
• Consider running openFPGALoader in sandboxed or containerized environments to limit potential impact

Patch Information

Users should monitor the openFPGALoader project for security updates addressing this vulnerability. Review the GitHub Security Advisory for the latest information on available patches and recommended versions.

Workarounds

• Only process .pof files from trusted and verified sources
• Implement file validation procedures before processing any .pof files
• Run openFPGALoader with reduced privileges and in isolated environments
• Use application sandboxing technologies (containers, VMs) to contain potential exploitation

# Example: Running openFPGALoader in a sandboxed environment
# Using firejail for basic sandboxing on Linux systems
firejail --private --net=none openFPGALoader --bitstream trusted_file.pof